Outer space has considerable debris as described in Committee on Space Debris, National Research Council; Orbital Debris: A Technical Assessment; National Academy Press, ISBM-10:0-309-05125-8; Wash., D.C. 1995. This debris around the earth has been created by the whole or parts of satellites and launch vehicles which have been placed in orbit, especially over the past four decades. Several of these objects were intentionally destroyed, as described by P. Hattis in The Growing Menace of Orbital Debris; Draper Laboratory; Livebetter Center for a Better Life; 2011, unintentionally exploded or intentionally blown up creating small debris. Such debris created in orbits which are higher than the earth's atmosphere will remain there indefinitely. The problem of debris impacting operating satellites is now recognized, and many developed countries have taken action to mitigate further growth in debris as described by D. Baiocchi and William Welser IV in Confronting Space Debris; Rand Corporation; ISBM-978-0-8330-5056-4. It has been recognized for decades that removal of debris should be accomplished, but nothing yet has been done due to economic, legal and political issues, as described by me in Rouge Commercial Geosynchronous Communications Satellites; IEEE Transactions on Broadcasting; BC-33, NO. 1; March 1987.
Communication and broadcast satellites can typically require up to $250 million for construction, launch and insurance. These satellites generally have a design lifetime of 15-18 years. Besides the cost of loss due to collision with orbital debris, the satellite may serve many millions of customers and its replacement typically takes three years. This results in serious loss of service to customers and of operating revenues.
Since debris is a hazard to operating satellites and the amount of orbital debris is still increasing, albeit at a slower rate than in the past, some satellite operators (including the manned International Space Station) take the information on debris location and orbit from ground radars, particularly the US government's NORAD radar complex, and send commands to move the operating satellites so their orbits avoid collision with the debris. The ground radar data become less effective as the distance to the debris increases and for smaller sizes of debris.